Microsoft's attempt to sidestep the industry debate over the meaning of "do not track" was sternly rejected on Wednesday.

The Internet body debating the privacy feature's official definition agreed that browsers with the setting turned on by default won't comply with industry standards.

The decision was a direct response to Microsoft's decision to ship Internet Explorer 10 with the feature turned on, automatically signaling to websites that the user doesn't want to receive targeted advertising. That announcement sparked immediate criticism from the online advertising industry and even some privacy advocates, who worried the move could derail fragile negotiations over the appropriate definition of do not track.

A committee of the World Wide Web Consortium made up of advertising, privacy and technical experts has been debating the industry standard for months, and had reached delicate compromises on several critical points. In the group's weekly phone call on Wednesday, members reached a consensus that mainstream browsers like Internet Explorer would comply only if the product shipped with the do-not-track option set to neutral.

Tabled was the question of how online sites and advertisers can respond to a default do-not-track setting. Representatives from companies including Google and Yahoo were pushing for the right to simply ignore such a request, several participants said.

That position falls in line with a voluntary industry agreement most online ad companies signed onto months ago, including Microsoft at the time. But that would effectively mean that no users of the next version of Internet Explorer could avail themselves of the do-not-track option, an outcome that troubled privacy advocates on the call.

"The fate of millions of users of IE10 is at stake," said Jeffrey Chester, executive director of Center for Digital Democracy. "The online companies think they can reject the IE signal with impunity. I think it's outrageous and shows what they think of consumers."

Google declined to comment, and Yahoo did not immediately respond to a request for comment. A Microsoft spokesman provided this statement: "We are engaged with the W3C, as we are with many standards groups. To say that a standard cannot support a privacy by default choice for consumers is odd to say the least."

Chester worries the continuing fallout from the Microsoft announcement could halt the tenuous progress of the consortium's discussions, removing pressure for the industry to abide by anything more than the watered-down voluntary standards.

A surprise move

Here's the background: Browser companies including Mozilla, Microsoft and Apple have begun putting do-not-track switches into their online browsers. But there's no legal mandate for any advertiser to follow the request - or even any agreed-upon industry standard for what abiding by it means.

The idea finally started to get some real traction earlier this year, when the Digital Advertising Alliance, which represents a large portion of online advertisers, agreed to honor do-not-track requests, at least by its own definition. The White House applauded the move.

Meanwhile, the consortium's committee took up the debate on appropriate industry standards. Both European Union and Federal Trade Commission officials have been watching the developments closely, occasionally signaling their preferred outcomes on key questions.

Lots of details remain in play, but there had seemed to be agreement on a rough outline.

Then Microsoft happened. The news that one of the four major browser companies would ship with default do-not-track altered the math and angered the industry.

"How they could turn around and unilaterally reject something that they've been working toward for five years is - well, fill in the blanks: It's a mystery, it's a disappointment, it's a frustration," Interactive Advertising Bureau Chief Executive Randall Rothenberg told AdExchanger.com.

The industry has since argued that the default setting was a settled question, which is why they were eager to clarify the issue on Wednesday.

Ignoring preferences

Unlike Chester, Stanford privacy researcher Jonathan Mayer read that as a positive development - at least insofar as it meant the industry side was still committed to the process.

He stressed that conversations have continued to take place in the days since Microsoft's announcement and that this month's critical W3C meeting scheduled for June 20-22 is still on track.

Mayer too, however, rejects the conclusion that advertisers should simply be allowed to ignore default do-not-track requests.

"You're blowing away preferences for a share of users who did set it deliberately," he said.

Microsoft defends its move.

"Our decision to provide IE10 customers a 'privacy by default' experience in an era when so much user data is collected online reflects our commitment to putting people first," a spokesman said. Federal Trade Commission Chairman Jon Leibowitz also applauded the move.

"Microsoft's do-not-track option in its upcoming version of Internet Explorer is yet another step forward in giving consumers choice about their browsing data," he was quoted saying.

Targeting Google?

But the cynical view is that Microsoft cares less about privacy - an issue on which its record is as spotty as most Internet companies - than it does its growing obsession with undercutting chief rival Google at every possible turn. The move allows it to differentiate IE in a way that might help stanch the loss of market share to Google's Chrome browser, while undermining Google's ability to generate ad revenue from IE users.

If the do-not-track negotiations get killed in the cross fire, so what? Microsoft still gets to proclaim its privacy virtues for embracing a standard that doesn't amount to much.

Even one Yahoo executive seemed to view Microsoft's decision in this light.

"Worried about DNT after MSFT blew it up w/ short-sighted announcement," Yahoo's Director of Public Policy Chris Sherwood tweeted last week from an account that says he's "tweeting in a personal capacity." "Get over Google, guys."